Metal powder metallurgy forming die based on hollow product machining

Abstract

The invention discloses a metal powder metallurgy forming die based on hollow product processing, which is based on the basic working principle of powder metallurgy, and is characterized in that firstly, the moving mode of an upper die core is improved, and the essence is that the upper die core cannot directly provide extrusion force; the upper die core is used as a key structure in the pressing process instead of a secondary sliding process which moves upwards along with the pressing action, the purpose is to preferentially reduce the extrusion force and avoid the problem that powder materials overflow and are wasted, but the upper die core is still used as a key structure in the pressing process, and in addition, a plurality of second-order material injection pipes are arranged to be matched with the structural appearance of a workpiece body. The second-order material injection pipe is matched with the compression molding process to carry out secondary material supplementing action, synchronous material supplementing is carried out on the basis of actively causing the problem of material shortage, and powder materials are uniformly filled in cooperation with the extrusion mode of the upper mold core; in the whole process, the completeness of the whole pressing action is judged according to the displacement change generated by the secondary material supplementing action on the material ejecting core.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a metal powder metallurgy forming die based on hollow product processing. Background Art

[0002] The essence of powder metallurgy process is to pressurize and mold metal powder, non-metal powder or a mixture of the two by high temperature. It is suitable for products with complex structures and shapes. Refer to the relevant content in the publication number CN103817326A. It is commonly used in the processing of gear parts.

[0003] Taking gear parts as an example, and considering saving material costs, conventional gear parts will have several additional holes and other optimized structures in addition to the mounting hole positions, so the punches used in the molding mold need to be customized according to the workpiece structure. It should be noted that the amount of powder in a single molding process is relatively consistent, but after the punch rushes into the mold cavity at a uniform speed, part of the powder is flushed out and lacks quantity due to the influence of the punch structure and shape. In addition, it will also affect the uniformity of powder filling, which will ultimately affect the subsequent molding quality.

[0004] This application proposes a solution to this problem. Summary of the invention

[0005] The purpose of the present invention is to provide a metal powder metallurgy forming die based on hollow product processing. For the powder metallurgy process of special products, because of the relatively special structure, when the punch punches into the cavity, it is affected by the shape of the punch structure, which directly affects the uniformity of powder filling and affects the subsequent forming quality.

[0006] The purpose of the present invention can be achieved by the following technical scheme: a metal powder metallurgy forming die based on hollow product processing, comprising a lower die seat, an upper pressure seat, an upper die core, a support seat, a workpiece body and a hydraulic power cylinder, wherein the support seat is located inside the lower die seat, a cavity corresponding to the workpiece body is formed inside the lower die seat through the support seat, and the upper die core is slidably connected in the cavity;

[0007] A directional slide is installed on the upper surface of the upper mold core, and the directional slide is slidably connected inside the upper pressure seat along its height direction. A plurality of second-order injection tubes corresponding to the workpiece body are installed in the directional slide, and a directional core column corresponding to the inside of the support seat is arranged on the lower side of the second-order injection tube, and the upper end of the second-order injection tube is arranged as a filling position.

[0008] It is further configured as follows: the upper pressing seat and the supporting seat are slidably connected along the height direction of the lower die seat through a hydraulic power cylinder.

[0009] It is further configured as follows: a plurality of first-order springs are installed between the upper press seat and the directional slide seat, and the upper end portion of the second-order injection pipe is slidably connected to the upper press seat.

[0010] It is further configured as follows: the lower end of the second-order injection tube extends into the cavity, and a reverse bevel is provided at the lower end of the second-order injection tube, and a bevel corresponding to the reverse bevel is provided at the upper end of the directional core column.

[0011] It is further configured that: a lifting core is slidably installed inside the directional core-inserting column along the vertical direction, and the top position of the lifting core is set to a cone angle.

[0012] It is further configured as follows: a displacement sensor is installed in the internal position of the support seat corresponding to the lower side of the directional plug column, the top end position of the transmission rod of the displacement sensor is installed on the lower side position of the material ejection core, and a second-order spring is installed on the outer position of the displacement sensor transmission rod.

[0013] It is further configured as follows: the directional core insert column is slidably connected inside the support seat, and the low point plane of the bevel in the directional core insert column is located at the lower side of the half plane of the workpiece body along the thickness direction.

[0014] The present invention has the following beneficial effects:

[0015] 1. Based on the basic working principle of powder metallurgy, the movement mode of the upper die core is improved. More specifically, the problem of "material shortage" of powder materials is actively caused during the pressing process, and the connection mode of the upper die core is changed. The upper die core does not directly provide extrusion force, but generates a secondary sliding process of upward movement during the pressing action, giving priority to reducing the extrusion force to avoid the problem of powder material overflow and waste. However, the upper die core is still the key structure in the pressing process;

[0016] 2. Based on the above content, several corresponding second-order injection tubes are set according to the structural shape of the workpiece body. The key to the second-order injection tube is to cooperate with the "lack of material" problem caused actively and perform secondary feeding action. The second-order injection tube moves synchronously during the downward movement of the upper mold core, and performs the secondary feeding action after moving to the corresponding distance. The key is: in the cooperation with the secondary feeding action, the extrusion force generated by the powder material causes the vertical movement of the ejector core, so that the displacement sensor is used to detect the movement mode and movement speed of the ejector core in real time, and the above content is used to judge the completion of the overall pressing action, so as to ensure that the powder material is fully filled to obtain a complete product body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is a schematic diagram of the structure of a metal powder metallurgy forming die based on hollow product processing proposed by the present invention;

[0019] Figure 2 The present invention proposes a metal powder metallurgy forming die based on hollow product processing Figure 1 sectional view of

[0020] Figure 3 This is a schematic diagram of the structure of an upper die core and a lower die base in a metal powder metallurgy forming die based on hollow product processing proposed by the present invention;

[0021] Figure 4 The present invention proposes a metal powder metallurgy forming die based on hollow product processing Figure 3 sectional view of

[0022] Figure 5 This is a cross-sectional view of a second-stage injection pipe in a metal powder metallurgy forming die based on hollow product processing proposed by the present invention;

[0023] Figure 6 The present invention proposes a metal powder metallurgy forming die based on hollow product processing Figure 5 Partial schematic diagram.

[0024] In the figure: 1. Upper pressure seat; 2. Lower die seat; 3. Second-order injection tube; 4. First-order spring; 5. Directional slide; 6. Upper die core; 7. Support seat; 8. Hydraulic power cylinder; 9. Displacement sensor; 10. Directional insert column; 11. Ejection core; 12. Second-order spring; 13. Workpiece body. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1: In the powder metallurgy process of special products, due to the relatively special structure, when the punch punches into the cavity, the shape of the punch structure directly affects the uniformity of powder filling and the subsequent molding quality. The following technical solutions are proposed:

[0027] Reference Figures 1 to 6 The metal powder metallurgy forming die based on hollow product processing in this embodiment includes a lower die seat 2, an upper press seat 1, an upper die core 6, a support seat 7, a workpiece body 13 and a hydraulic power cylinder 8. The support seat 7 is located inside the lower die seat 2. A cavity corresponding to the workpiece body 13 is formed inside the lower die seat 2 through the support seat 7, and the upper die core 6 is slidably connected in the cavity;

[0028] A directional slide 5 is installed on the upper surface of the upper mold core 6, and the directional slide 5 is slidably connected inside the upper pressure seat 1 along its height direction. A plurality of second-order injection tubes 3 corresponding to the workpiece body 13 are installed in the directional slide 5, and a directional core column 10 corresponding to the inside of the support seat 7 is arranged on the lower side of the second-order injection tube 3, and the upper end of the second-order injection tube 3 is arranged as a filling position. The upper pressure seat 1 and the support seat 7 are slidably connected along the height direction of the lower mold seat 2 through a hydraulic power cylinder 8.

[0029] Basic principle: The essence of powder metallurgy process is compression molding, which is specifically applied to hollow products such as gear parts. In the compression molding process, the punch needs to be reset according to the product structure and shape. In this regard, the structure and shape of the second-stage injection pipe 3 and related continuations are not described in the present invention. It should be noted that:

[0030] In the specific operation process, the upper die core 6 and the support seat 7 are first reset to the initial position, and then the powder raw materials after the proportioning are put into the cavity. Under the power of the hydraulic power cylinder 8, the upper die core 6 is driven to be completely squeezed into the cavity, and the powder raw materials are fully pressed to form a workpiece body with a corresponding structural shape. In this process, it should be explained that:

[0031] Because the second-stage injection tube 3 will also be immersed in the cavity, a corresponding product structure is formed for the local position of the second-stage injection tube 3. After the pressing is completed, the upper pressing seat 1 is reset, and the supporting seat 7 is driven upward by the hydraulic power cylinder 8, so that the pressed workpiece body 13 is squeezed out of the cavity for the next pressing and forming process.

[0032] Embodiment 2: This embodiment improves the conventional powder metallurgy process, as follows:

[0033] A plurality of first-order springs 4 are installed between the upper press seat 1 and the directional slide seat 5, the upper end portion of the second-order injection tube 3 is slidably connected to the upper press seat 1, the lower end of the second-order injection tube 3 extends into the cavity, and a reverse bevel is provided at the lower end of the second-order injection tube 3, an angle corresponding to the reverse bevel is provided at the upper end of the directional insert column 10, a lift core 11 is slidably installed in the vertical direction inside the directional insert column 10, and the top end of the lift core 11 is set at a cone angle;

[0034] A displacement sensor 9 is installed in the internal position of the support seat 7 corresponding to the lower side of the directional insert column 10. The top end of the transmission rod of the displacement sensor 9 is installed on the lower side of the top core 11, and a second-order spring 12 is installed on the outer position of the transmission rod of the displacement sensor 9. The directional insert column 10 is slidably connected in the internal position of the support seat 7, and the low point plane of the bevel in the directional insert column 10 is located at the lower side of the half plane of the workpiece body 13 along the thickness direction.

[0035] Solution description: The key to conventional powder metallurgy technology lies in the pressing process, specifically the direct pressing method. However, in this process, on the one hand, the powder material overflows, resulting in a problem of material shortage in the workpiece body 13. In addition, the uneven filling of the powder material affects the molding quality of the workpiece body 13. To address this problem, the present invention proposes the following pressing process:

[0036] S1: In this embodiment, the upper mold core 6 is still used as the key structure in the pressing process, but the movement process of the upper mold core 6 is different, which is specifically manifested as follows: when the upper mold core 6 moves into the cavity and contacts the powder material and starts to press, the upper mold core 6 generates an upward reaction force due to the resistance of the powder material, so that the directional slide 5 receives the reaction force from the upper mold core 6 and starts to move from bottom to top inside the upper press seat 1, the purpose of which is to reduce the squeezing force on the powder material and avoid directly causing the powder material to overflow. In this process, after the first-order spring 4 is continuously compressed and reaches the maximum compression amount, the directional slide 5 will not continue to move upward, so that the upper mold core 6 provides a "complete" squeezing force on the powder material;

[0037] S2: Based on the content of S1, as the upper mold core 6 continues to move, the second-stage injection tube 3 will also move downward synchronously. In this process, because the lower end of the second-stage injection tube 3 is located at the lower side of the upper mold core 6, the second-stage injection tube 6 can be used to replenish the inside of the cavity. Its essence is: replenishing the material synchronously during the pressing action, so it can be understood that: the obvious difference between the present invention and conventional powder metallurgy is that in the initial state, the entire quantitative powder material will not be injected into the cavity, but the pressing action and the injection action will be performed synchronously.

[0038] Embodiment 3: The following description is made in combination with the relevant contents of Embodiment 1 and Embodiment 2:

[0039] S3: If the weight of powder material required for a single pressing is M, then the powder material put into the cavity in the initial state is only 0.85xM. In actual circumstances, the pressed workpiece body 13 has a problem of material shortage, and thus it is necessary to continuously add 0.15-0.17xM of powder material through multiple second-stage injection pipes 3, which is specifically manifested as follows:

[0040] Because the directional slide 5 tends to move upward during the pressing process, when the lower side of the upper press seat 1 just contacts the upper surface of the lower die seat 2, it means that the overall pressing process is completed and combined with Figure 6 As the pressing action continues, the distance between the lower end of the second-stage injection tube 3 and the upper side of the directional core plug column 10 gradually decreases, but after the pressing action is completed, there is still a gap between the lower end of the second-stage injection tube 3 and the upper side of the directional core plug column 10;

[0041] And refer to Figure 5 Because the second-stage injection pipe 3 needs to perform a secondary feeding action, the remaining powder material can be injected by pressurization. In this process, the ejector core 11 is squeezed by the powder material and tends to move downward until the top position of the ejector core 11 moves to a position lower than the upper end plane of the directional insert column 10, and the powder material is replenished into the cavity again;

[0042] S4: It should also be noted that: because the ejector core 11 is continuously moved downward by the extrusion force of the powder material, the displacement sensor 9 can continuously detect the moving speed of the ejector core 11, and the moving speed of the ejector core 11 is used as an important parameter for feedback of the pressing process. The specific reason is that: if there is a large degree of material shortage problem inside the cavity, and when the top end of the ejector core 11 moves to the upper end position of the corresponding directional plug column 10, a part of the powder material can be quickly filled into the cavity, then the powder material inside the second-stage injection tube 3 can be added to the cavity in a "simpler" way;

[0043] On the contrary, when the degree of material shortage in the cavity is low or there is no obvious material shortage, the powder material in the second-stage injection tube 3 will no longer enter the cavity, and the pressure generated by the powder material added in the second-stage injection tube 3 will only act on the top material core 11, causing the top material core 11 to continue to move downward, and in this process, the moving speed of the top material core 11 is proportional to the powder material added in the second-stage injection tube 3, that is, the greater the pressure generated by the powder material, the faster its moving speed;

[0044] S5: Integrate the contents of S1 to S4. If the thickness of the workpiece body 13 is H, then the thickness of the cavity should be H, that is, when the distance between the upper mold core 6 and the support seat 7 is equal to H, it means that the pressing is completed. However, it should be noted that: during the pressing and forming action, when the distance between the upper mold core 6 and the support seat 7 is greater than or equal to 1.09 to 1.15xH, the secondary feeding action is performed through the second-order injection pipe 3, and the upper mold core 6 continues to move downward by 0.09 to 0.15xH. This process needs to make full use of the displayed value in the displacement sensor 9. The feeding amount per unit time in the secondary feeding action performed by the second-order injection pipe 3 is constant;

[0045] If the display of the displacement sensor 9 has obvious fluctuations, it is necessary to further control the moving speed of the upper mold core 6, the purpose of which is to complete the pressing and forming action by providing a stable extrusion force, and refer to Figure 6 The purpose of limiting the low point plane of the bevel in the directional insert column 10 to be located at the lower side of the half plane of the workpiece body 13 along the thickness direction is that the powder material added from the second-stage injection tube 3 is mainly concentrated in the lower side of the cavity, because the powder material accumulated at the lower side due to the extrusion force is "evenly spread" into the remaining material-deficient space.

[0046] In summary: based on the basic working principle of powder metallurgy, the movement mode of the upper die core is improved first. Its essence is: the upper die core does not directly provide extrusion pressure, but produces a secondary sliding process of upward movement as the pressing action is carried out. Its purpose is to prioritize reducing the extrusion pressure to avoid the problem of overflow and waste of powder material. However, the upper die core is still a key structure in the pressing process. In addition, a number of second-order injection pipes are set according to the structural shape of the workpiece body. The second-order injection pipes cooperate with the pressing process to perform secondary feeding actions. On the basis of actively causing the problem of "lack of material", synchronous feeding is performed, and the extrusion method of the upper die core is cooperated to make the powder material evenly filled. In the whole process, it is also necessary to cooperate with the displacement change of the top core caused by the secondary feeding action to judge the completion of the overall pressing action.

[0047] The above are examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A metal powder metallurgy forming die for hollow product processing, comprising a lower die seat (2), an upper pressure seat (1), an upper die core (6), a support seat (7), a workpiece body (13) and a hydraulic power cylinder (8), characterized in that: The support seat (7) is located inside the lower die seat (2), and a cavity corresponding to the workpiece body (13) is formed inside the lower die seat (2) through the support seat (7), and the upper die core (6) is slidably connected in the cavity; A directional slide (5) is installed on the upper surface of the upper mold core (6), and the directional slide (5) is slidably connected inside the upper pressure seat (1) along its height direction. A plurality of second-stage injection tubes (3) corresponding to the workpiece body (13) are installed in the directional slide (5), and a directional insert column (10) corresponding to the inside of the support seat (7) is arranged at the lower side of the second-stage injection tube (3), and the upper end of the second-stage injection tube (3) is arranged as a material replenishing position.

2. The metal powder metallurgy forming die based on hollow product processing according to claim 1, characterized in that: The upper pressing seat (1) and the supporting seat (7) are slidably connected along the height direction of the lower die seat (2) via a hydraulic power cylinder (8).

3. The metal powder metallurgy forming die based on hollow product processing according to claim 1, characterized in that: A plurality of first-order springs (4) are installed between the upper pressure seat (1) and the directional slide seat (5), and the upper end portion of the second-order injection pipe (3) is slidably connected to the upper pressure seat (1).

4. The metal powder metallurgy forming die based on hollow product processing according to claim 1, characterized in that: The lower end of the second-stage injection tube (3) extends into the cavity, and a reverse bevel is provided at the lower end of the second-stage injection tube (3), and a bevel corresponding to the reverse bevel is provided at the upper end of the directional core plug column (10).

5. The metal powder metallurgy forming die based on hollow product processing according to claim 4, characterized in that: A lifting core (11) is slidably mounted inside the directional core insert column (10) in a vertical direction, and the top end position of the lifting core (11) is set at a cone angle.

6. The metal powder metallurgy forming die based on hollow product processing according to claim 5, characterized in that: A displacement sensor (9) is installed in an internal position of the support seat (7) corresponding to the lower side of the directional plug column (10), the top end of the transmission rod of the displacement sensor (9) is installed on the lower side of the material ejection core (11), and a second-order spring (12) is installed on the outer side of the transmission rod of the displacement sensor (9).

7. The metal powder metallurgy forming die based on hollow product processing according to claim 4, characterized in that: The directional insert column (10) is slidably connected in the inner position of the support seat (7), and the low point plane of the bevel in the directional insert column (10) is located at the lower side of the half plane of the workpiece body (13) along the thickness direction.

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